1. Field of the Invention
The present invention is in the field of accumulator devices and is directed more particularly to a high flow accumulator device characterized in that the same is provided with auxiliary means for preventing premature or unwanted closure of the oil port.
2. The Prior Art
The use of accumulator devices, and particularly high capacity accumulator devices as a mechanism for energy storage is today commonplace. In many applications a high capacity accumulator is charged by the introduction of oil under pressure into the body of a pressure vessel divided into two chambers by an expansible bladder member. The introduction of oil into one chamber works to further compress gas confined in the second chamber to the opposite side of the bladder to store energy.
The stored energy in the compressed gas is utilized by connecting a work load to receive the output of oil expelled from the pressure vessel through an oil port.
In a typical construction, a poppet valve is moveably mounted in the oil port and is urged by spring pressure to an unseated condition whereat a portion of the valve extends into the pressure vessel and the oil port is open. Ideally, when the pressure drops in the hydraulic line connected to the work load to such degree that the gas pressure exceeds the oil pressure in the line, the oil is progressively forced past the open valve and to the load. When the oil has been substantially completely forced from the vessel by the expanding bladder, the bladder is intended to engage against the head of the poppet, urging the same downwardly against the force of the poppet support spring and into seated position, sealing the oil port, whereby extrusion of the bladder through the port is prevented.
It has been discovered that in many instances in the devices heretofore known, the poppet valve seats prematurely, not as a result of contact with the expanding bladder but, rather, as a result of pressure differentials to opposite sides of the poppet valve head, such pressure differentials resulting from sudden extraction or flow of oil in the line to the work load and consequent pressure drops in the areas immediately below the valve head. In such instances the poppet valve may be sucked or drawn into contact with the valve seat, resulting in premature interruption of flow in the line to the work load.
The noted phenomenon is experienced particularly frequently in closed circuit or cyclically operated hydraulic systems wherein, for instance, the accumulator may be charged from a pump and thereafter the circuit to the pump interrupted, the work function being effected solely by energy derived from the discharging accumulator.
In order to combat the premature seating of the poppet due to flow conditions and pressure differentials, it has been proposed to increase the force of the poppet valve control spring which urges the valve toward the open position. However, by thus increasing the force of the spring. The valve may be retained open even after it is engaged by the bladder with resultant extrusion of the bladder through the open oil port.